What do I have to do to get an extension for business income tax?

We grant an automatic extension of time to file your business tax return based on the return type and due date. This extension does not grant you an extension of time to pay any tax you owe. If you determine that you will owe tax, you must file the payment voucher associated with your return type (see below) to pay any tax you owe to avoid penalty and interest on tax not paid by the original due date of your return. If you do not expect to owe tax, you do not have to do anything.

Form
Return Type
Voucher
IL-1120
Corporation Income and Replacement Tax
IL-1120-V
IL-1120-ST
Small Business Corporation Replacement Tax
IL-1120-ST-V
IL-1065
Partnership Replacement Tax
IL-1065-V
IL-1041
Fiduciary Income and Replacement Tax
IL-1041-V
IL-990-T
Exempt Organization Income and Replacement Tax
IL-990-T-V

If you have additional inquiries, you may submit them to the Questions, Comments, or Request form.